Computational Studies of the Molecular Basis of Natural and Acquired Resistance to Extremes in Microbes

项目总结 我们的长期目标是了解微生物如何能够经受住 温度、压力和化学组成(P-T-X)，通过确定大分子如何 组成微生物的结构被保存下来。我们的重点是高压的影响，这是非常重要的 人们对温度的影响知之甚少。由于高压方法越来越多地被用于 灭菌和食品保存，了解压力的极限对人类健康和 福利。一个令人不安的发现是，一些中温微生物似乎能够承受~10kbar的压力 压力，而“压力菌”，即在高压下茁壮成长的微生物，已经被发现达到最大。 压力只有~1.1千巴。因此，一个总体目标是帮助定义微生物可以 恢复正常状态后的忍耐和恢复，这与确定是否 病原微生物可以通过确定什么压力可以永久地在高压处理中存活下来。 破坏细胞内环境中蛋白质的结构。 我们提议的工作的首要问题是，中温生物如何快速发展10千巴 考虑到压电体只在1.1千巴下被发现，电阻。我们的假设是酶来自于 实际上，亲压剂在高压下比中温剂和压电剂更稳定。 (微生物对压力的反应上调渗透压)可能会进一步保护酶不受高浓度 压力。特别是，压电体可能会导致整个生物体迅速获得抗压性。 我们的具体目标是： 目标1.测试现有的P和T范围的力场，并在需要时开发新的力场。 目的2.确定柔韧性-稳定性平衡对嗜中性菌和嗜热菌的酶的影响 在超高P。 目的3.研究压电体对超高P值条件下酶的影响。

PROJECT SUMMARY Our long-term goal is to understand how microbes are able to withstand remarkable extremes of temperature, pressure, and chemical composition (P-T-X), by determining how the macromolecular structures comprising the microbes are preserved. Our focus is on effects of high pressure, which are much less understood than temperature effects. Since high-pressure methods are increasingly being used for sterilization and food preservation, understanding the limits of pressure is important for human health and welfare. A disturbing finding is that some mesophilic microbes appear to able to withstand ~10 kbar pressures, while “piezophiles”, microbes that thrive at high pressures, have been found at maximum pressures of only ~1.1 kbar. Thus, an overall aim is to help define the limiting pressures that microbes can endure and recover from upon return to normal conditions, which is relevant to determining whether pathogenic microbes can survive high pressure treatments, by determining what pressures will permanently disrupt structures of proteins in the intracellular environment. Our over-arching question for the proposed work is how mesophiles can rapidly develop 10 kbar resistance given that piezophiles have been found only at 1.1 kbar. Our hypotheses are that enzymes from piezophiles are actually more stable at high pressure than those from mesophiles and that piezolytes (osmolytes up-regulated by microbes in response to pressure) may further protect enzymes from high pressure. In particular, piezolytes could lead to rapidly acquired pressure resistance for the entire organism. Our specific aims are: Aim 1. To test existing force fields for a range of P and T and to develop new force fields if needed. Aim 2. To determine the effects of the flexibility-stability balance on enzymes from mesophiles and piezophiles at ultra-high P. Aim 3. To determine the effects of piezolytes on enzymes at ultra-high P.